R = 30*12      # 30 years until retirement
T = 60*12      # 60 total years
g = 0.002      # deposit is 0.2% larger each month
B0 = 100000    # initial balance is $100,000
D1 = 1000      # initial savings is $1,000 (per month)
W = 10000      # withdraw $10,000 per month in retirement

mn = 0.005     # mean monthly return
sd = 0.04      # std dev of monthly return
nsims = 1000   # number of simulated